I. Cities of refuge were needed, because the 'avenger of blood' was recognised as performing an imperative duty. 'Blood for blood' was the law for the then stage of civilisation. The weaker the central authority, the more need for supplementing it with the wild justice of personal avenging. Neither Israel nor surrounding nations were fit for the higher commandment of the Sermon on the Mount. 'An eye for an eye, and a tooth for a tooth,' corresponded to their stage of progress; and to have hurried them forward to 'I say unto you, Resist not evil,' would only have led to weakening the restraint on evil, and would have had no response in the hearers' consciences. It is a commonplace that legislation which is too far ahead of public opinion is useless, except to make hypocrites. And the divine law was shaped in accordance with that truth. Therefore the _goel_, or kinsman-avenger of blood, was not only permitted but enjoined by Moses. But the evils inherent in his existence were great. Blood feuds were handed down through generations, involving an ever-increasing number of innocent people, and finally leading to more murders than they prevented. But the thing could not be abolished. Therefore it was checked by this institution. The lessons taught by it are the gracious forbearance of God with the imperfections attaching to each stage of His people's moral and religious progress; the uselessness of violent changes forced on people who are not ready for them; the presence of a temporary element in the Old Testament law and ethics. No doubt many things in the present institutions of so-called Christian nations and in the churches are destined to drop away, as the principles of Christianity become more clearly discerned and more honestly applied to social and national life. But the good shepherd does not overdrive his flock, but, like Jacob, 'leads on softly, according to the pace of the cattle that is before' him. We must be content to bring the world gradually to the Christian ideal. To abolish or to impose institutions or customs by force is useless. Revolutions made by violence never last. To fell the upas-tree maybe very heroic, but what is the use of doing it, if the soil is full of seeds of others, and the climate and conditions favourable to their growth? Change the elevation of the land, and the `flora' will change itself. Institutions are the outcome of the whole mental and moral state of a nation, and when that changes, and not till then, do they change. The New Testament in its treatment of slavery and war shows us the Christian way of destroying evils; namely, by establishing the principles which will make them impossible. It is better to girdle the tree and leave it to die than to fell it.